SILVERTON, Colo. (AP) – Authorities are still trying to find two people who are believed to have been killed in a small plane crash in the southwest Colorado mountains.

A search team reached the crash site Sunday and found two bodies. Autopsies are planned for Monday.

The single-engine plane was flying from Durango to Aspen with four people onboard when it crashed Saturday afternoon. The crash site was about 1 1/2 miles north of Silverton, local officials said.

None of the victims’ names has been released, and the cause of the crash was unknown. The National Transportation Safety Board will investigate.

(credit: CBS)

The Socata TB-21 left Durango at about 1:30 p.m. Saturday. About 40 minutes later, its emergency beacon signal was detected near Silverton, The Denver Post reported.

Bad weather cut short the search on Saturday. Temperatures in Silverton dipped to 4 degrees between Saturday night and Sunday morning, and eight to 10 inches of snow had fallen at the scene after the crash, San Juan County Emergency Manager Kristina Maxfield said.

The plane crashed in a rugged, heavily forested area up to 11,000 feet above sea level, Maxfield told The Associated Press.

Maxfield said a search team reached the crash site Sunday and found two bodies, which were being carried to waiting vehicles, and an autopsy was planned for Monday. She and Federal Aviation Administration spokesman Mike Fergus both confirmed to the AP that there were no survivors.

Neither elaborated as to exactly how they knew the other two people were dead, but Fergus said the debris field covered 1 1/4 miles. Maxfield said the nature of the crash was one factor in the determination, though she did not provide further details.

She also noted that any possible survivors would have had to endure a night of freezing temperatures and snow on the mountain.

It was unclear how long the search for the other victims would continue Sunday because snowfall had resumed and visibility was worsening, Maxfield said.

It was the second fatal plane crash near Silverton this year. A pilot and passenger were killed in the July 14 crash of a small plane. The cause is still under investigation.